Chapter 8, Problem 8.19P

In the Rankine cycle for a steam power plant the turbine entry and exit enthalpies are 2803 kJ/kg and 1800 kJ/kg, respectively. The enthalpies of water at pump entry and exit are 121 kJ/kg and 124 kJ/kg, respectively. The specific steam consumption (in kg/kW.h) of the cycle is_

Evaluate the modifications made to the basic Rankine cycle to improve the overall efficiency of steampower plants. Include the reheat and regenerative cycles, along with economizers and pre-heaters.Discuss both the advantages and disadvantages of these modifications. Support your analysis withdiagrams.

provide a step by step solution for the following question in the added image

On the diagram below sketch a basic Rankine cycle with superheating. Assume that there are irrevesibilities in the turbine and pump. Identify the device associate with each process. Make sure to label: the states and include important features, e.g. lines of constant temperature, volume, pressure, entropy, vapor dome, etc.

As indicated in Fig. P8.52, a power plant similar to that in Fig. 8.11 operates on a regenerative vapor power cycle with one closed feedwater heater. Steam enters the first turbine stage at state 1 where pressure is 12 MPa and temperature is 560 C. Steam expands to state 2 where pressure is 1 MPa and some of the steam is extracted and diverted to the closed feedwater heater. Condensate exits the feedwater heater at state 7 as saturated liquid at a pressure of 1 MPa, undergoes a throttling process through a trap to a pressure of 6 kPa at state 8, and then enters the condenser. The remaining steam expands through the second turbine stage to a pressure of 6 kPa at state 3 and then enters the condenser. Saturated liquid feedwater exiting the condenser at state 4 at a pressureof 6 kPa enters a pump and exits the pump at a pressure of 12 MPa. The feedwater then flows through the closed feedwater heater, exiting at state 6 with a pressure of 12 MPa. The net power output for the cycle is 330…

As indicated in Fig. P8.52, a power plant similar to that in Fig. 8.11 operates on a regenerative vapor power cycle with one closed feedwater heater. Steam enters the first turbine stage at state 1 where pressure is 12 MPa and temperature is 560 C. Steam expands to state 2 where pressure is 1 MPa and some of the steam is extracted and diverted to the closed feedwater heater. Condensate exits the feedwater heater at state 7 as saturated liquid at a pressure of 1 MPa, undergoes a throttling process through a trap to a pressure of 6 kPa at state 8, and then enters the condenser. The remaining steam expands through the second turbine stage to a pressure of 6 kPa at state 3 and then enters the condenser. Saturated liquid feedwater exiting the condenser at state 4 at a pressureof 6 kPa enters a pump and exits the pump at a pressure of 12 MPa. The feedwater then flows through the closed feedwater heater, exiting at state 6 with a pressure of 12 MPa. The net power output for the cycle is 330…

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3. A medium size power station is used to produce 30 MW net power for a refinery. The station uses steam as the operating fluid and operates according to the Carnot cycle between the pressure limits of 0.4 bar and 35 bar. Steam enters the boiler as a saturated liquid and leaves it as a dry saturated vapour. (vii) Using the highest and lowest temperature values in the cycle, recalculate the efficiency of the cycle and show that it is equivalent to the result in part (vi). (viii) Calculate the thermal efficiency of the power station if the isentropic efficiency of the steam turbine is 94%. (ix) State main disadvantages of using the Carnot cycle as the basis for a power station. (x) State the name of the cycle that is used in practice in power stations, along with three key benefits over the Carnot cycle.

Evaluate the performance of gas power cycles for which the working fluid remains a gas throughout the entire cycle.